Navigational guide system



Jan. 14, 1936. J H A N JR 2,027,527

NAVIGATIONAL GUIDE SYSTEM Original Filed Aug. 17, 1929 10 Shee'ts-Sheet 1 [N VEN TOR. FE J0b n Hays f/ammonafl Jr:

BY W 1 1- M.

Jan. 14, 1936. J. H. HAMMOND, JR

' NAVIGATIONAL GUIDE SYSTEM Original Filed Aug. 1'7, 1929 10 Sheets-Sheet 2 m w QM mm S. S .WLJ ww w n V J \ERQ b1 Wm o n I, mm M? mw kw W ATTORNEY Jap. 14, 1936. J. H. HAMMOND, JR 2,027,527

NAVIGATIONAL GUIDE SYSTEM 7 Original Filed Aug. 17, i929 10 Sheets-Sheet 3 IN VEN TOR. Jafin A a s flammond, Jr.

#K awn-m ATTORNEY Jan. 14, 1936. J. H. HAMMOND, JR 2,027,527

NAVIGATIONAL GUIDE SYSTEM Original Filed Aug. 17 1929 10 Sheets-Sheet 4 INVEN TOR. John Hag/s HammomiJr.

I\ ATTORNEY Jan. 14, 1936. J. H. HAMMOND, JR

NAVIGATIONAL GUIDE SYSTEM Original Fi led Aug. 17, 1929 10 sheets-sheet 5 1936- I J. H. HAMMON-D, JR 2,027,527

NAVIGATIONAL GUIDE SYSTEM Original Filed Aug. 17, 1929 10 Sheets-Sheet 6 INVENTOR. I Jo/m Hays f/ammoncg J' ATTORNEY Jan. 14, 1936. J. H. HAMMOND, JR 2,027,527

NAVIGATIONAL GUIDE SYSTEM Original Filed Aug. 17, 1929 10 Sheet$Sheet'7 INVENTOR. Jo/m Hays Hammond, Jr?

.ITORNEY Jan. 14, 1936- J. H. HAMMOND, JR

NAVIGATIONAL GUIDE SYSTEM Original Filed Aug. 17, 1929 10 Sheets-Sheet 9 IN VEN TOR. Jo/m Hays HammonafiJ. BY Wu M MNN ATTORNEY NEW Jan. 14, 1936.

AMPLIFIER J. H. HAMMOND,

NAVIGATIONAL GUIDE SYSTEM Original Filed Aug. 17, 1929 10 Sheets-Sheet 10 q [259 T i- INVENTOR.

ATTORNEY visibility is poor.

Patented Jan. 14, 1936 NAVIGATIONAL GUIDE SYSTEM John Hays, Hammond, Jr., Gloucester, Mass.

Application August 17, 1929, Serial No. 386,587

Renewed December 7, 1934 This invention relates to a navigational guide system, and more particularly to a system for designating to a pilot his position with reference to a fixed location.

This invention as specifically applied to a aeronautical guide system provides for a means whereby the. pilot of an aircraft may be informed of his position with reference to a landing field, and is particularly adaptable in cases where the This system is particularly ad-' vantageous in cases where the aircraft is flying at night or in foggy weather, or when'the clouds intervene between the aircraft andthe land.

The invention contemplates a system whereby signals emanating from the aircraft are impressed upon a plurality of direction finders located in various parts of the field. These direction finders are oriented in order to effect a predetermined responsiveness. A plotting mechanism is provided which is actuated in response to the orientation of said direction finders and which designates the position of the aircraft upon a facsimile of the terrane of thelanding field. This facsimile of the landing field with the position of the aircraft designated thereon,

.is transmitted to the pilot by television. The elevation of the aircraft above the ground is determined from the direction finders and transmitted to the aircraft as part of the picture. The position of the plane in relation to the landing field, being designated as a continuous operation, the pilot can observe how he is moving with respect to the 'terrane and can therefore which safely guide his aircraft towards a landing-field.

This invention has been described with reference to its application to an aircraft but it is obvious that it may be applied to any moving craft such as a boat or a submarine. i

The invention also consists in certain new and original features of construction and combinations of parts hereinafter set forth and claimed.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of its operation and the manner of its organization may be better understood by referring to the following 'description'taken in connection with the accompanying drawings forming a part thereof, in

Fig. 1 shows a-birds eye view: of a landing field and surrounding country.

Fig. 2 is a side elevation of one of the direction finders with its associated receiving system,

Fig. 3 is a front elevation of one of the direction finders.-

Fig. 4 is a front elevation of the plotting mechanism.

Fig. 5 is a sectional view taken on line 5-5 5 of Fig. 4.

Fig. 6 is a rear elevation of the plotting mechanism showing the chart and markers to be transmitted.

Fig. 7 is a sectional elevation taken on line 1-1 of Fig. 5.

Fig. 8 is a sectional elevation taken on line 8-8 of Fig.5.

Fig. 9 is a detail of the light source of the plotting mechanism indicated in Fig. 6.

Fig. 10 is a detail of one of the light projectors of the plotting mechanism indicated in Fig. 4.

Fig. 11 is a plan view of the television transmitting apparatus used in connection with the plotting mechanism.

Fig. 12 is a sectional elevation of the airplane showing the television receiver and the signal transmitter. a

Fig. 13 is an elevation of the instrument board of the airplane.

Fig. 14 is a diagram of the signal transmit ting apparatus.

Fig. 15 is a sectional view showing a modified form of television receiving apparatus in the airplane.

Fig. 16 is a section taken on line lG-IG of Fig. 15.

Fig. 17 is a sectional view of a television receiving apparatus employing a Braun tube for a receiving means; and

Fig. 18 isa perspective of aground receiving apparatus which may be used to take the place r of the radio direction finder shown in Fig. 2.

- Like reference characters denote like parts in the several figures of. the drawings.

In the following description and in the claims parts will be identified by specific names. for convenience, but they are intended to be as generic in their application to similar parts as the art will permit.

In-the adaptation of the invention to an aeronautical system shown in Fig. 1, the landing field is indicated at 20, and the three direction finder stations at 2 I, 22, and 23. The approach.-

a ing airplane is shown at 24, and the television transmitting station at 25. Other objects of the landscape are shown, such as a hill 26, a forest chimneys 3| and 32. 5s

The projection of the airplane on the surface of the earth is indicated at the point 33. Joining this point with the three direction finder stations are three lines 35 and 36, which form azimuth angles R. S. T. with lines drawn from the direction finder stations to the center of the field 31. From the plane, 3 lines, 40, M and 42 are drawn to the three finder stations. These lines form elevation angles A, B, and C with the lines 34, 35 and 36, respectively.

The airplane 24 transmits a wireless signal which is picked up by the direction finder shown in Fig. 2. This direction finder consists of a pick up device in the form of a coil 45, wound around a frame of insulating material 46, which is rigidly secured to a shaft 41. This shaft has hearings in a frame 48, which is pivotally mounted on a base 49. Secured to the shaft 41 is a worm wheel 5I, which meshes with the worm 52 mounted on a shaft 53, which has bearings in p the frame 48. To this shaft is fastened a handie 54 and a gear 55, which meshes with a second gear 56 carried by the shaft of an electrical transmitter 51, which is connected to an electrical cable 58.

Any suitable transmitter and the, associated repeater may be used such as are fully described to the other end is a gear 65, which meshes with a. second gear 66 mounted on the shaft of an electrical transmitter 61, which is connected to an electrical cable 68.

The coil 45 is connected to two flexible conductors H and 12. The conductor H is connected to the grid of a vacuum tube 13, and the conductor 12 is connected to one side of the filament of this tube. The other side of the filament is connected through a variable resistance 14, to one side of a battery 15, the other side of which is connected to the conductor 12. This battery is enclosed in a metallic box 16, which is connected through a condenser 11 to the ground. Across the conductors H and 12 is mounted a variable condenser 18 and a balancing condenser 18. This latter consists of two sets of fixed plates 8| and 82, and a set of movable plates 83, which are connected to ground. The plate of the vacuum tube 13 is connected to one side of the battery' 84, the other side of which is connected to one end of the primary of a transformer 85, the other end of which is connected by a conductor 86 to the conductor 12. One side of the secondary of the transformer is connected to the grid of a second vacuum tube 81, and to one sideof a condenser 88. The other side of this condenser is connected to the other side of the secondary, and also to one side of the filament of the tube 81, and the other side of this filament is connected through a. variable resistance to a filament battery 89. The other side of this battery is connected to the condenser 88; and a conductor 9|.

The plate of the tube 81 is connectedto one side of a battery 92, the other side of which is connected to a conductor 33. The conductors 9| and 03 are. connected by a flexible lead to a pair of headphones 34. 4

The plotting mechanism shown in Figs. 4 to 10 consists of a frame IOI, in which is rotatably mounted a shaft I02. Pinned to the shaft I02 is a bracket I03, upon which is mounted a disc I 04, Fig. 7. Secured to this disc are three electrical repeaters I5, I06 and 501. These are similar to the type described in Patent No. 1,431,140 previously referred to. Secured to the shafts of these repeaters are three pinions I08, I06 and III) which mesh with three gears III, H2 and H3. These gears are mounted on shafts H4 (see Fig. 10) which are mounted in insulating bushings H5, carried by brackets 6. These shafts are also mounted on insulating bushings II 1 in the plate I04. Secured to the end of the shaft H4 is a light casing I I8, in which is mounted a small incandescent lamp I I9. Pressing against the central terminal of this lamp is a spring I2I, which is mounted on a piece of insulation I22, carried by the light casing H8. This spring is always in contact with the metallic plate I84. Mounted in the end of the casing Il8 is a suitable set of lenses I23, which cause the light from the lamp I I9 to be formed into a parallel beam. Coverbeam to be projected on the plate I04, as a nar- 7 row ray of light.

The three repeaters I05, I06 and I01 control three of these light projectors, I 21, I28 and I 29, as seen in Fig. 4. The three beams of light emitted by the light projectors I21,-- I28 and I29 are shown in I3I, I32 and I33 respectively. It will be noticed that the three light p'rojectors are located in positions on the disc I04, which correspond to the positions of the direction finders 2 I, 22 and 23, with respect to the landing field 20. This field is outlined at I34 on the disc I04. It will be noticed, however, that the shape of the landing field and the positions of the three light sources are a mirror image of the actual relative position of the landing field and range finders.

The frame IN is provided with extensions MI and I42, in which is fixedlymounted a plain rod I 43 and in which is rotatably mounted a threaded rod I 44. Slidably mounted on the rod I43 is an eye piece I40, in which is mounted a lens system I45, which is focused on the plate I04 so as to magnify the image of this plate. Cross hairs I46 are mounted in the optical system I45, thus indicating the central point of this system. This optical system is carried in a frame I41, which is slidably mounted on the rod I43, and is threaded ct on to the shaft I44. Secured to one end of the shaft I44 is a handle I48, and on the other end is a bevel gear I40. On the back of the plate I 04 are mounted I4 circular segments of conducting material I5I to I64, (see Fig. 7); The segment 'ried by a piece of insulation I66, mounted on the disc I04. This contact brush engages the shaft of the gear H2. The contact segment I62 is connected to a similar brush, engaging the s'haftof the gear I I3," and the contact segment I63 is connected to a third brush, engaging the shaft of the gear III. The contact segment I64 is connected to the plate I04. Engaging the 14 contact segments I5I to I64 are 14 brushes, I1,I to I84, which are connected to 14 conductors I9I.to 204. The brushes "I to I84 are mounted on a block of insulating material I88, which is mounted on the frame Ill.

Secured to the other end of the shaft I82 is a bracket 286, to which is fastened a circular plate 281. The outer face ofthis disc is provided with a map of the country surrounding the landing field 28, with the heightsof the various objects ofthe landing indicatedthereon as shown in Fig.6.; a 1 i Loosely mounted on the shaft m is a as m, i to the hub of which is pinned a pointer 28!. "The gear 288 meshes with th'elpinion of an electrical repeater2l I, which is mounted on thedisc 281. Secured to, but insulated from thedisc 281, are

.four circular contact ts 2E2 to 215. The segment 2I2 is connected to the common return mounted on the fixed rod 23! is a'block of insulating material 233, in which is mounted a lamp 234, oneslde of which is connected to a brush 235, which engages the rod 231, and the other side is connected to a threaded block of conducting material 236 see Fig. 9, which is secured to the block of insulating'material 233. The rod 23l is connected to a=conducton 231, and the frame III is connected to a coriductor238, of a supply. Pivotally mounted under the block 236is an arm 239 came end of whichis rotatably mounted aroller 288, which rides over the plate; 281 and which is preferably provided with a soft rubber periphery. Secured to the arm 239 is afpointer 2|8. i i a 7 On one end of the threaded shaft 232 is pinned a collar 2, and onthe other end is pinned a bevel'gear 242,'which meshes with another bevel gear 243. This gear ispinned to one end of a shaft 2, which has bearings in the frame l8l. To the other end of'the shaft 288 is pinned a bevel gear 245- which meshes with thebevel gear I89.

Secured to the rotated by anelectrical repeater 255, which is mounted on the frame 18!. The a wires of this repeater are indicated at256 to 259. Rotatably mounted in the frame IN is a shaft 26!, to which is secured a gear 262, which meshes with a pinion 263, rotatedby an electrical repeater 264, which ismounted -on the frame IN. The four wires of this repeater are indicated at 266 to 269. Secured to the shaft 26l is adrum 2, which is provided-with teeth 212. Rotatably'mounted in;

the frame l8l are two 5118115113 and 218 see Figlfi, onwhich are mounted two drums 215 and 216.. Wound to these drums is a long strip ofv flexible material 211, on which is marked a series of numbers corresponding to various altitudes.

This strip" passes over the 21!, and is bracket as Fig. 8 a worm wheel 286, which mesheswith'a worm 241 mountprovided with a plurality of perforations 218 see Fig. 8, which are engaged by the teeth 212. Inside the drums215 and 216 are coil springs 215' (not-shown), which tend to turn these drums in a clock-wise and counter clockwise direction respectively, in reference to Fig. 5. In this manner, the strip 211 is always kepttaut over the drum 2".

For transmitting the signals from the airplane a signal transmitter 28| is provided in the airplane 282 (see Figs. 12 and 14) The transmitter is supplied with current from a wind driven generator 283, the twoleads from which are connected through a switch 288, to a primary of a transformer 285, one side of the winding of which is connected to the grid of an oscillator tube 286, the other side of the winding of the transformer 285' being connected through a battery 281, to one side of the filament of the tube 286. The plate of this tube is connected through an inductance" 288, and abattery 289, to the same side of the filament. The plateof this tube is also connected to the plate of a second vacuum tube 29!, through an inductance 292. The plate of the second tube 29l is connected through a condenser 293, to a tuned circuit 298, consisting of a capacity 295 and an inductance 296, one side of which'is grounded. Adjustably connected to the inductance 296 is a conductor 291, which is connected to the antenna, as will be described in connection with Fig. 12. The grid of the tube -29| is connected through a grid leak 298 and an inductance 299 to the ground. This system forms a simple oscillator, the output of which is modulated by the tube 29 I.

The conductor 291 (see Fig. 12), is connected 385 is mounted on a gear 386, whichmeshes with a pinion 381, the ratiobetween the two being two-to one. The pinion 381 is mounted on the shaft of a motor 388, which is supported from theframe of the airplane. On the shaft of this motor is mounted a drum 3| I, provided with a plurality of holes 3l2, arranged on a helix on the periphery of this drum. In front of the drum 3 is mounted a lens 3| 3, in an opening in the instrument board 318. Mounted above this lens 4 is a standard compass 3| 5. Mounted inside of the drum 3 is a photo electric cell 3l6, which is connected by a cable 3" to a television receiver 3 i8. This may be of any suitable and well known construction. The television receiver is connecta edby a conductor 319 to the brush 388 and the brush 383 is connected to a trailing antenna32l.

The motor 388 supplied by current from the wind driven generator 283, this supply being controlled by a synchronizing means322, and a contrcl'means 323, which is operated by the aviator, so as tosynchronize the drum 3| l with the transmitting apparatus on the ground.

For transmitting a view of the disc 281, a television transmission apparatus 'is provided as shown-in Fig. 11. This consists of a casing 33| in the endof which is mounted lens 332, which focuses the image of the disc 281 on the surface of a drum 333. This drum is provided with a plurality of holes 338, arranged along the line 0 a helix on this drum. The drum 222 and the location of the holes 224 are similar to the drum 2 and the holes 2I2. The drum 222 is moimted on the shaft of a motor 225, which is supported on a bracket 222, secured to the casing 22I. The motor 225 is driven from a source of supply not shown, and its speed is controlled by a synchronizing mechanism 221. The synchronizing mechanisms 221 and 222 may be of any standard and well known construction for television systems. Also connected to the supply, are two lights 228 and 229, for illuminating the disc 201. Mounted inside the drum 223 is a lens 240 and a photo electric cell 3, which is connected by a cable 342, to a television transmitting apparatus 242, which may be of any well known construction, the output or which is connected to an antenna 244.

In the operation of this form or the invention when an airplane 24 approaches the landing field 20, signals will be sent from the transmitter 22I over the conductor 291, brush 20I, commutator 205, brush 202, to the antenna 22L nals will be sent intermittently due to the rotation of the commutator 205 and will be received by the three direction finder stations 2I 22 and 23. This reception is accomplished by the loop 65, which picks up the signals which are amphfled by the tubes 12 and 21, and are then heard in the phones 94. The two systems 01 receptions which may be used are either the maximum or the minimum eiiect with the coil 42. It is found, however, that the minimum effect gives the most accurate results so that system will be described here, though the maximum efiect may be used when round to be advantageous.

With the system using the minimum effect, the I on the side oi. the coil connected to the grid is equal to the capacity to ground on the side connected to the filament. This restores the sharpness of the position of minimum signal. The ground connection of the compensating condenser should be symmetrically placed so that the compensating adjustment or the condenser will be independent o! the location of the transmitter.

For the initial adjustment of the apparatus, the coil 45 is set so that its plane is vertical, and so revolved that the projection on the field o! the normal to this plane passing through the center 0! the coil, also passes through the center of the landing field point 21 of Fig. l. The other two direction finders are similarly oriented. The three light projectors I21, I22 and I22 in Fig. 4 are also adjusted so that the projection of the beams 01' light, pass through the center of the field which is indicated by the point 21. The circuits from the three transmitters 21, of the three direction finders 2|, 22, and 22 to the three repeaters I05, I02, and I". are hen closed. This is accomplished by closing switches which are not shown, connecting the four wires in the three cables 20 to the four wires of the three repeaters I05, I02 and I01. Batteries not shown are inserted in the common wires of these circuits.

At the same time switchesare closed which are These siglocated adjacent to each direction finder 2I, 22 and22,andwhichturnonandofithelightheaml I2I, I22 and l22,byclosingoropeningthecircuitl through the conductors III, 222 and 222, brushes I22, I22 and III, I22, I22 and "I to the brushes I22, thence along shatts II4, casings II2, to lamps III. The current returns through springs I2I, plate. I24, segment I24, brush I24; conductor 224, through a battery back to the switches located adjacent to the direction finders.

When an airplane 24 approaches the field 22 signals are transmitted from the airplane as already described, and are received by the three direction finders 2i, 22 and 22. The signals received by thue direction finders are-heard in the head phones 24, and the operator orients the coil 42 by means of the handles 24 and 64, so that a minimum signal isreceived in the head phones 24. When this condition occurs the plane of the coil is normalto a line from the airplane to the center 01' the coil. The azimuth angles R. S, T. through which the three coils have been turned from their initial positions are transmitted by the electrical transmitters 21 to the three repeaters I05, I06 and I01, which cause the gears III, H2

and I I3 to be rotated through these angles, thereby turning the three light sources I21, I28 and I29 through the three angles R. S. T. as shown in Fig. 4. The point where the three light beams I2I, I22 and I22 intersect on the disc I24 corresponds to the projection 22 of the airplane 24,

onthesurfaceoitheearth. Thelenssystemisthen disposed so that the cross hairs I46 are in register with the point of intersection of the three .light beams. This is effected by turning the cranks I42 and 242'which respectively cause the lens system to slide along the rod I42 and the plates 221 and I24 to rotate in unison. The rotation of the screw thread I44 is transmitted by means of bevel gears I42-245 and 242-242 to the slider 222, so that this slider will always be disposedin registered relationship with the lens system I45. Thus the lamp 224 will be located with respecttothemaponthedisc 221 inthe same position that the airplane is with relation to the landing field 22.

As the plate 221 is rotated, and the block 222 is moved longitudinally, the arm 222 and roller 242 will take up a trailing position, the axis of which will be the same as the line of flight of the planewithrespecttothe ground,andthiswill be indicated on the map by the position of the pointer 2I2. In this way not only the location of the plane on the map is shown, but also the direction in which it is fiylng.

The picture or this map, together with the position of the lamp 224 are picked up by the television transmission apparatus mounted in the eas- 8 22I (see Fig- 11). This is a standard System in which the motor 225, rotates the drum 222 at a uniform speed by means of the synchronizing mechanism 221 and the holes 224 in this rotating drum scan the image formed by the lens 222 on the face of this drum. The light transmitted through these holes is focused by the lens 240 on to the photo electric cell 2, the current from which is amplified by the transmitter 242, and sent out as wireless waves from the antenna 244. These wireless signals are then received by the antenna 22I, which conducts them to the brush 222, (Fig. 12). Dining halt the revolution 01' the commutator 225, the signals are conducted to the brush 224, and thence by the conductor 2I9, to the television receiver SIB, where they are amphfied in a well known manner. The amplified signals are then impressed upon the neon tube SIB or othersuitable variable source of illumination to control the light emitted therefrom. The light from the tube 3l6 passes through the holes 3l2 in the drum 3, as this drum is rotated by the motor 300, and forms an image of the map on the lens 3" as shown in Fig. 13. The speed of the motor 303 which is controlled by the synchroniz ing means 322 maybe varied by turning the handle 323, so that the aviator can always correct for slight .variations of the synchronizing means. The aviator therefore, will always have in. front of him a view of the: landing field and the surrounding country with a bright spot, indicating the position of hisv plane withrespect to the landing field. He can also ,tell the direction of the wind by means of the pointer 209, the velocity of the wind being given in the upper right hand corner, and the altitude of the plane above the landing field in the lower right hand comer. The velocity of the wind is determined by any suitable means such as a wind velocity meter, and is set on the dial 252- by meansof the repeater 255, which is actuated by a transmitter which is either operated automatically or manually by the wind velocity meter. The movement of the transmitter is then imparted to the dial 252 through pinion 254 and gear 253.

The altitude of the plane is determined by,

measuring the angles A, B and C which are transmitted by the transmitters 51 on the three direcinstrument board l4, is an altimeter II, which indicates to the pilot his elevation above the ground. This altimeter may be of any suitable.

construction and maytake the form of radio altimeter described in Science and Invention for February 1929, pages 952 and 953, vthistype of altimeter operating in response to the reflection from the ground of radio waves'propagated from the plane.

his elevation.

Instead of omitting every other picture as de-, scribed in'the previous'system, a system may be used as shown in Fig, 15, which omits only a single line in each picture during which time transmission of the signaltakes place. In this system the drum 3| l, carries a circular segment of insulating material 40l, on' which is mounted acircular segment of conducting'inaterial 402, provided with av slot. 403 and a tongue 1404. Rollingon these segments are three rollers 405, 406and 401, which are mounted on a strip ofinsulation 408, carried by the frame of the airplane. Rollers 405, 406 and 401 are connected to conductor 3l9, antenna 32| and conductor 291. l U a In this fsystm, the brushes 405, 406 are electrically connected by the segment 402 during the complete revolution, with exception of a. brief The pilot is informed therefrom of his altitude above the ground from two different sources and thereby has afurther assurance of rest of the revolution, however, the television receiving apparatus is connected to the antenna, so that the image of thefield is being formed on the lens as. i

In place of the television system already described, one using a Braum tubemay. be used. This television system is described in the patent of John Hays Hammond, Jr. No. 1,725,710 issued August to, 1929, and entitled Systems andmethods of television.

In place of the radio pick-up device of the direction finders shown in Fig. 2, a system of sound direction finding may be used, as shown in Fig. 18. This consists of a plurality of horns 421, located in a frame 422, which corresponds to the frame 48 of Fig. 2. At the end of these horns are mounted microphones 423, which are connected in series to an amplifier 424. The output of this amplifier goes to the head phones 94. This system is operated in the same manner as that described in connection'with Fig. 2, so that the plane of the frame 422 vwill be normal to the line joining the direction finder to the. plane when a maximum signal is received in the head phones 94.

It is to be noted that the pilot will be able to see constantly the horizontal position of his plane with respect to a fixed location such as a landing field. He is also informed of his elevation above the ground and his direction of flying, so that he has an accurate survey of the characteristics of the landing field and his exact position with reference thereto, so that if the pilot isdestined to the landing field he will be able to make asafe landing under any conditions which may be ad- I verse to the visibility of the field.

While certain novel features of the invention have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes in the forms and details of the deviceillustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. 1

What I claim is:

'1. In an aeronautical guide system, a pluralit of direction finders, including pick-up devices, meansfor orienting. said pick-up devices in accordance with the direction of the signals emitted from an aircraft, whereby said members will respond with predetermined effect to the signals impressed thereon, and means. responsive to the orientation of said pick-up devices for transmitting theazimuthal angle of rotation of saidpickup devices to a plottingmechanism, whereby the location of the projection of the aircraft upon the earthcan be determined, a transmission system comprising scanning means for scanning said plotting mechanism, and a receivingsystem in said aircraft for receiving andtranslating signals transmitted by said last mentioned transmission system. 1 I

2. In combination with an aircraft having means for transmitting signals, a plurality ofdirection finders, each thereofincluding a pick-up device, means for rotating said pick up devices in azimuth in accordance with the direction of the signals emitted fromthe aircraft, independent means for rotating each of said pick-updevices about a horizontal axis in accordance with the direction of the signals emitted from the aircraft, automatic means for transmitting the angle of azimuthal rotation of each of 'said pickupdevices to a plotting mechanism whereby the location of the projection of the aircraft upon the landing field may be determined, andmeans for transmitting the angle of rotation of each 01' the pickup devices about its horizontal axis to a range finder whereby the elevation of the aircraft above the ground may be determined.

3. A landing field guide system which comprles in combination with an aircraft, a plurality of direction finders disposed in various parts of an aircraft landing field, said direction findersincluding si al pick-up devices, means for sending signals from the aircraft, means for orienting said pick-up devices according to the direction of the signals, a plurality of rotatably mounted light projecting members located to-correspond in mirror image relationship with the position of said direction finders on the landing field, said projecting members being rotatably responsive to the orientation of said pick-up device, whereby the rays emitted from said members meet at a point, a picture of the landing field and intenmediate vicinity, and a position designating me ber associated with said picture, means for actu ating said member so as to place it in a position on said picture corresponding to the displacement of the intersecting points of the rays whereby the course of the projection of the aircraft on the landing field or its intermediate vicinity is traced on said picture, and means for transmitting said picture and the course traced by said designating member to the aircraft.

4. In a plotting mechanism of the class de-- scribed, a rotatable disc, a designating means associated with said disc, a roller membersecured to said designating means and adapted to cooperate with the face of said disc, means for effecting a relative parallel displacement between said designating means and said disc, and a pointer affixed to said designating means whereby the direction of'the resultant displacement of the designating means with respect to the disc will be indicated thereon.

5. In a system for guiding an aircraft towards a landing field, a plurality of direction finders, a plotting mechanism comprising a first and second rotatable disc, a plurality of light projecting members mounted on said first disc, and rotatably operable in accordance with the orientation of said direction finders, an eye piece, means for efi'ecting a relative parallel displacement of said eye piece with respect to said first disc, whereby said eye piece can be maintained in registration with the intersection of the rays emitted from said light projecting member, a designating member mounted for indication with respect to said second disc, and means operable in accordance with the relative displacement of said first disc and said eye piece for effecting a corresponding relative displacement of said designating member and said second disc.

6. A navigational guide system which comprises in combination with a moving craft, means for propagating signals from said craft, a plurality of direction finders located at a distance from said craft, said direction finders including signal pick-up devices, means for orienting said pick-up devices from a fixed direction in accordance with the direction of the signals emitted from the said craft, whereby said devices will respond to said signals with predetermined characteristics; a first rotatable disc, a second rotatable disc associated with said first disc and mounted in aligned parallel relationship therewith, a plurality of light projecting members mounted on said first disc and located to correspond in mirror image relationship with the position 01' said direction finders, said projecting members -being rotatably responsive to the orientation of said pick-up device whereby the rays emitted from said member meet at a point, an eye piece mounted for observation of said rays, means for effecting a relative parallel displacement of said eye-piece with respect to said first disc, whereby said eye piece can be maintained in registration with the intersection of the rays emitted from said light projecting members, a designating member mounted for indication with respect to said second disc, means operable in accordance with the relative displacement of said first disc and said eye piece for effecting a corresponding relative displacement of said designating member and said second disc, and means for informing the pilot of the craft his position with reference to a fixed location as indicated by said second disc and the designating member associated therewith.

7. The combination of a craft having means for transmitting signals, a plurality of receiving stations having means for receiving signals transmitted by said craft and for determining the direction of the incoming signals, a' television transmission system including a picture surface comprising a chart, means controlled by said receiving stations for determining the position of said craft relative to said chart, a transmission system comprising a scanning means for scan-- ning said chart and a receiving system in said craft for receiving and translating signals transmitted by said last mentioned transmission system.

8. The combination of a craft having means for transmitting signals, a plurality of receiving stations having means for receiving signals transmitted by said craft and for determining the direction of the incoming signals, a television transmission system including a picture surface comprising a chart of the immediate vicinity of said stations and for producing a plurality of beams of light controlled by said receiving stations for determining the position of said craft on said chart, a transmission system comprising a scanning means for scanning said chart and a receiving system in said craft for receiving and translating signals transmitted by said last mentioned transmission system.

9. The combination of a craft having means for transmitting signals, a plurality of receiving stations having means for receiving signals transmitted by said craft and for determining the direction of the incoming signals, a television transmission system including a picture surface comprising a chart of the immediate vicinity of said station, means for producing a plurality of beams of light controlled by said receiving stations for determining the position of said craft on said chart, a transmission system including a scanning means for scanning said chart, a receiving system on said craft for receiving and translating signals transmitted by said last mentioned transmission system and means on said craft for alternately transmitting signals first referred to and receiving signals from said last named transmission system.

10. The combination of a craft having means for periodically transmitting signals, a plurality of receiving stations having means for receiving signals transmitted by said craft and for determining the direction of the incoming signals, a television transmission system including a picture surface comprising a chart representing in miniature the layout of the land in the vicinity oi the said stations, means comprising a plurality of light sources disposed with respect to said chart in the same relative positions as said receiving stations with respect to the location represented by the chart controlled by said receiving stations for determining the positionand the direction of travel on said chart of said craft, a transmission system comprising a scanning-means for scanning said chart and a receiving system on said craft for receiving and translating signals transmitted by said last mentioned transmission system.

landing port, scanning means associated with the television transmitter, control circuits extending between the central stationand each of the receiving stations, mechanical means connected in said control circuits and responsive to the orientation of said loops at said directional receiving stations for determining the point on the model indicated as the intersection. ofthe loop directions, the scanning means of the television transmitter being positioned relative to the model so as to permit scanning the model and the displace- 11. In a navigational guide system, a mobile able means whereby signals may be transmitted by the television transmitter from which signals may be derived a picture of the model and displaceable means, a receiver on said mobile body adapted to receive the energy emitted by the television transmitter to thereby indicate on the mobile body the position of the mobile body with respect to the landing port.

12. In a navigation system, a craft having means for transmitting signaling energy, a bea- 10 con station comprising receiving stations disposed in geographically separated positions along the route of the craft and a central station,'said receiving stations each including means comprising an actuatable loop antenna for receiving the signaling energy transmitted by the craft and for determining the direction of the incoming energy, said central station being provided with a television transmission system includinga picture surface comprising a. chart or replica of the immediate vicinity of the beacon station, control circuits between the central station and each of the receiving stations said control circuits including means responsive to the actuation of said loop antennae for determining the point indicated as the intersection of the loop directions, a displaceablemeans associated with the chart for indicating the position of the craft on the chart and a scanning means arranged so as to .scan the chart to thereby transmit signals from said transmission system which signals are capable of being translated into a picture of the chart and the displaceable means and a receiving systemon the craft for receiving and translating signals transmitted by the television transmission system.

JOHN HAYS HAMMOND, JR. 

